As a Mobile Engineer at Stubhub, you are responsible for building and optimizing the primary gateway through which millions of live event fans discover, purchase, and access tickets. The mobile application is the core of the Stubhub experience, acting as a digital ticket wallet, an interactive seating guide, and a marketplace. Engineers in this role must build highly performant, reliable, and responsive interfaces that function flawlessly even under challenging network conditions, such as those inside crowded stadiums and concert venues.

Your work directly impacts the platform's conversion rates, user retention, and overall brand trust. You will tackle complex engineering challenges, including real-time inventory synchronization, interactive 3D seat mapping, offline ticket rendering, and secure transaction processing. Because a ticket purchase is often a high-anxiety transaction for fans, your attention to detail in UI smoothness and state management is vital to delivering a seamless experience.

This role requires a unique blend of deep platform knowledge (whether iOS or Android), robust architectural design capabilities, and a product-focused mindset. You will collaborate closely with product managers, UX designers, and backend teams to translate complex business requirements into clean, modular, and maintainable mobile code. At Stubhub, mobile is not just a channel; it is the heart of the business.

The questions you will encounter during the Stubhub interview process are designed to test your core computer science fundamentals, platform-specific knowledge, and system design capabilities. These questions are drawn from real candidate experiences and reflect the actual scenarios you will face during your evaluation.

Coding & Algorithmic Problem-Solving

These questions evaluate your understanding of data structures, algorithm design, and computational efficiency, with a strong emphasis on recursion and data manipulation.

• Write a function to recursively flatten a deeply nested dictionary or JSON object into a single-level dictionary.
• Implement an algorithm to recursively merge two nested dictionaries, resolving conflicts based on a specified strategy.

Preparing for an interview at Stubhub requires a structured approach that balances deep technical knowledge with practical, hands-on application design. You should focus on demonstrating not just that you can write code, but that you understand how your code behaves in a production environment under real-world constraints.

Technical Execution & Code Quality – Interviewers at Stubhub look for clean, readable, and maintainable code. You must demonstrate a strong command of your chosen language (Swift or Kotlin) and platform APIs, showing that you can write efficient algorithms and structure your UI cleanly.

Architectural Design & Scalability – You must show that you can design mobile systems that are modular, testable, and robust. This involves choosing the right architectural patterns (such as MVVM, VIPER, or MVI), managing application state predictably, and designing clean APIs between the mobile client and backend services.

Problem-Solving & Analytical Thinking – When faced with complex or ambiguous requirements, your ability to break down the problem, communicate your thought process, and make logical trade-offs is critical. Interviewers value candidates who ask clarifying questions before diving into code.

Product & User Empathy – Because Stubhub is a consumer-facing application, you should always keep the end-user experience in mind. Be prepared to discuss how your technical decisions impact app performance, responsiveness, accessibility, and overall user satisfaction.

The interview process for a Mobile Engineer at Stubhub is highly structured, rigorous, and designed to evaluate both your practical coding skills and your high-level architectural thinking. The process is sequentially gated, meaning you must successfully pass each stage before moving on to the next. This ensures that both your time and the team's time are focused on high-probability matches.

The journey begins with a standard recruiter screen to align on your background, expectations, and role fit. This is followed by a technical screen, which often involves a live-coding exercise focusing on core computer science concepts like recursion or data structure manipulation. Once you pass the initial screening, you will receive a detailed preparation document outlining the onsite or virtual loop expectations, which is a highly praised resource that helps demystify the upcoming evaluations.

The main loop consists of three distinct, deep-dive interviews. "The Discipline" is a technical project deep dive where you present and defend a complex project from your past. The "Mobile Code Pair" is a practical, hands-on round where you add features to a starter project in real-time. Finally, the "Mobile System Design" round tests your ability to architect complex client-side systems.

This visual timeline illustrates the typical progression from your initial contact to the final decision phase. Candidates should expect the entire process to take between three to five weeks, depending on scheduling availability. Use this timeline to pace your preparation, ensuring you allocate sufficient time to practice live coding before the technical screen and system design before the final loop.

To succeed at Stubhub, you must understand exactly what is being evaluated in each specialized round of the interview loop. The following sections break down the core evaluation areas, detailing what strong performance looks like and the specific concepts you need to master.

Mobile Code Pair (Live Coding)

This practical round is designed to simulate a real day on the job. You will be provided with a starter project—with the option to work in SwiftUI or UIKit for iOS engineers—and asked to implement specific features live. The starter project usually centers around core Stubhub concepts, such as managing event listings or a shopping cart.

Be ready to go over:

• State Management – How to cleanly pass data between views, handle UI updates, and maintain a single source of truth.
• Asynchronous Operations – Fetching data from a mock API, handling loading states, and ensuring the main thread is never blocked.
• UI Layout & Responsiveness – Building clean, adaptive layouts that scale across different screen sizes using modern layout frameworks.
• Advanced concepts (less common) – Custom transition animations, complex list virtualization, and local caching mechanisms.

Example scenarios:

• Add an interactive "Favorites" toggle to an event list starter app, ensuring the state persists when navigating back and forth between screens.
• Implement a real-time countdown timer within a ticket checkout flow that gracefully handles backgrounding and foregrounding of the app.
• Build a search filter over a pre-populated event list, optimizing the rendering performance to prevent any UI stuttering during fast typing.

Mobile System Design

In this round, you will step back from the code to design a large-scale mobile feature or application architecture. The focus is on modularity, data flow, offline capabilities, and network efficiency.

Be ready to go over:

• App Architecture – Selecting and justifying an architectural pattern (e.g., MVVM-C, Clean Architecture) that supports team scaling and testability.
• Offline Synchronization – Designing robust caching, storage (CoreData, SQLite, Room), and synchronization strategies for offline ticket access.
• Network & API Design – Structuring efficient payloads, defining endpoint contracts, and handling flaky network transitions inside crowded stadiums.
• Advanced concepts (less common) – Dynamic feature delivery, server-driven UI architectures, and real-time synchronization protocols like WebSockets or Server-Sent Events (SSE).

Example scenarios:

• Architect a mobile ticket wallet that guarantees secure, offline retrieval of barcode data at a stadium venue with zero cellular reception.
• Design a real-time, interactive venue seating map that dynamically updates seat availability and pricing as other users purchase tickets.
• Design an image-delivery and caching pipeline for a high-traffic event discovery feed, ensuring minimal memory footprint and smooth scrolling.

The Discipline (Technical Project Deep Dive)

This unique round focuses on your ability to communicate complex technical concepts, defend your architectural decisions, and reflect on past engineering trade-offs. You will lead a discussion on a significant technical project you have shipped in a previous role.

Be ready to go over:

• Technical Decision Making – Why you chose specific technologies, frameworks, or architectures over viable alternatives.
• Problem Resolution – How you identified, debugged, and resolved unexpected technical bottlenecks or scaling issues during the project lifecycle.
• Collaboration & Influence – How you aligned other engineers and cross-functional stakeholders around your technical vision.
• Advanced concepts (less common) – Post-release monitoring, crash-rate optimization, and measuring the direct business impact of your technical changes.

Example scenarios:

• Present a migration project where you transitioned a legacy codebase to a modern architecture, detailing how you managed risk and minimized regression.
• Describe a performance optimization initiative where you successfully reduced app launch time or memory usage, explaining the profiling tools and methodologies used.

As a Mobile Engineer at Stubhub, your daily responsibilities extend far beyond writing code. You are an active participant in shaping the product roadmap, optimizing engineering workflows, and maintaining the operational health of the mobile applications.

You will spend a significant portion of your time collaborating with product managers, UX designers, and backend engineers to define feature specifications and API contracts. This cross-functional collaboration ensures that the mobile client is considered early in the product design phase, preventing integration bottlenecks later. You will help design APIs that are optimized for mobile network constraints, ensuring payloads are lightweight and endpoints are structured logically.

On the engineering side, you will write clean, well-tested Swift or Kotlin code, conduct thorough code reviews for your peers, and contribute to the evolution of the mobile codebase's architecture. You will also be responsible for maintaining high test coverage through unit and UI automation tests. Additionally, you will monitor production health using crash reporting and performance monitoring tools, proactively identifying and resolving regressions to maintain a highly stable app store rating.